A vehicle transmission includes for an electric drive vehicle a clutch for selectively drivingly connecting an input shaft and an output shaft through a gear set. A clutch collar rotationally drives one or more axially aligned rows of at least two and preferably three drive members, such as ball bearings. The clutch collar is movable between drive position in which the input shaft and output shaft are drivingly engaged through two drive members, a park position in which one drive member is rotationally fixed to the housing, and a tow position in which the drive members are disengaged from the input shaft.
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17. An electric battery driven vehicle comprising an electric motor drivingly engageable with a transmission for transmitting power from the electric motor, the transmission comprising a housing, an axially extending input shaft, an output shaft, a gear set, and a clutch for selectively drivingly connecting the input shaft and the output shaft through the gear set,
the clutch comprising a collar and a first axially extending row of drive members rotationally drivingly engaged with the collar,
the clutch movable between (a) a first position in which the input shaft and output shaft are drivingly engaged through the gear set, (b) a second position in which the output shaft is rotationally fixed to the housing, and (c) a third position in which the input shaft is disengaged from the output shaft.
1. A transmission comprising:
a housing, an input shaft rotatable about an axis, an output shaft, a gear set, and a rotatable clutch assembly coaxial with the input shaft for selectively drivingly connecting the input shaft and the output shaft through the gear set,
the clutch assembly comprising a clutch collar and two axially spaced drive members, each drive member separate from the clutch collar and rotationally drivingly connected to the clutch collar,
the clutch collar axially movable between (a) a drive position in which the input shaft is drivingly engaged with one drive member and the output shaft is drivingly engaged with the input shaft through the other drive member and the gear set, (b) a park position in which the gear set is drivingly engaged with one drive member and the other drive member is rotationally fixed to the housing, and (c) a neutral position in which the two drive members are disengaged from the input shaft.
12. A transmission comprising:
a housing, an axially extending input shaft having an outer surface defining a spline, an output shaft, a gear set, and a clutch for selectively drivingly connecting the input shaft and the output shaft through the gear set,
the clutch comprising a collar coaxial with and surrounding the input shaft, the collar having a cylindrical inner surface, the inner surface defining an axially extending groove,
two spherical drive members in driving rotational engagement with the collar through the collar groove,
the collar axially movable between (a) a drive position in which one drive member is drivingly engaged with the input shaft and the other drive member is drivingly engaged with the gear set, (b) a park position in which one drive member is drivingly engaged with the gear set and the other drive member is rotationally fixed to the housing, and (c) a neutral position in which the two drive members are drivingly engaged with the gear set.
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The present invention relates to vehicles and more particularly to gear shifting arrangements.
Various devices for transferring power in a vehicle transmission are known to those skilled in the art. One such device is a shifting collar utilized as part of a collar shift transmission. Collar shift transmissions are commonly used in certain vehicles such as all-terrain vehicles, but may be utilized in numerous other types of vehicles. Collar shift transmissions may be manually or power shifted. Examples of the collar shift transmission assemblies can be found in U.S. Pat. Nos. 7,406,888 and 8,261,899, the disclosures of which are hereby incorporated by reference. In these prior designs, shift collars having internal or external drive splines are utilized to engage corresponding drive splines on gears and other components such as a park flange. Drive spline engagement and disengagement can require significant force, especially when the transmission is under torque, for example, when the vehicle is fully loaded and parked on an incline or decline. It would be beneficial to reduce the engagement or disengagement force for easier and smoother operation of the transmission.
The present invention is a gearbox or transmission comprising including a housing, an input shaft, an output shaft, a gear set, and a clutch assembly for selectively drivingly connecting the input shaft and the output shaft through the gear set. The clutch assembly includes a clutch collar and at least two, and preferably three, axially spaced drive members, such as ball bearings, rotationally drivable by the clutch collar. The clutch collar is movable between (a) a Drive position in which the input shaft is drivingly engaged with one drive member and the output shaft is drivingly engaged with the input shaft through the other drive member and the gear set, (b) a Park position in which the gear set is drivingly engaged with one drive member and the other drive member is rotationally fixed to the housing, and (c) a Tow position in which the two drive members are disengaged from the input shaft.
Preferably, the clutch assembly includes internal grooves for driving engagement with the drive members, and a third drive member for assisting in alignment of various drive grooves for easier shifting. The clutch preferably includes several rows of circumferentially aligned drive members, each row circumferentially spaced around the inner cylindrical surface of the collar. A cage may be utilized to hold the drive members in axial and circumferential alignment.
Referring to
Referring to
A clutch assembly 36 selectively drivingly engages rear output shaft 34 with front output shaft 38 to provide selective four-wheel drive. The clutch assembly 36 includes a clutch collar 37 which may be selectively splined to the front and rear output shafts as is well known in the art. The collar is axially movable by a small electric motor 39 which drives a shift fork 35 engaged with the collar 37.
The input shaft 20 and related components are shown in more detail in
A park flange 44 includes a cylindrical portion 46 coaxial with and surrounding the input shaft 20 and an integral annular portion 48. The annular portion 48 is locked to the housing assembly 12 by cap screws 49 to prevent relative movement. An annular stop flange 47 is integral with the annular portion 48. The outer surface of the cylindrical portion 46 includes a series of axially extending ball grooves 45. Ball grooves 22, 41, and 45 are for engagement with drive members, preferably steel ball bearings, as will be described herein. A generally cylindrical shift collar assembly 50 surrounds the input shaft 20.
A generally cylindrical cage 60 is positioned within the shift collar 52. The cage may be constructed of a metal or a polymer. Spiralox retaining rings 66 are positioned in annular grooves 67 formed on the radially inner surface of the shift collar 52, one adjacent each axial end. A wave spring 68 is positioned within the shift collar 52 between one of the retainer rings 66 and an axial end surface of the cage 60. The wave spring 68 biases the shift collar 52 into engagement with the opposite axial end surface of the cage 60.
In one preferred embodiment, the cage 60 includes twenty-four circular apertures 62 for containing eight rows 58 of axially aligned drive members 64 in the form of steel balls. Each ball 64 is permanently rotationally drivingly engaged with the collar 52 through the grooves 56. The diameter of each steel ball 64 is about 0.25 inches, but the present invention is not limited to any particular ball size or material. For example, other metals or polymers may also be preferred in certain transmissions. The ball grooves 22, 41, 45, and 56 have radii generally the same or slightly larger than the ball radii to promote rolling and alleviate frictional contact. In a preferred embodiment, all of the balls 64 are identical, but other embodiments may utilize balls having varying sizes, with the corresponding groove radii varying accordingly.
Referring to
The spacing and arrangement of the balls 64 is important in the shifting capability of the collar assembly 50 as will be explained herein. Of course, the number of grooves 56 and corresponding circumferential ball columns 59 may vary depending on the load requirements. Any number of ball rows 58 may be used; for example, four or even fewer ball rows 58 may be adequate for some applications. As will be seen, regardless of the number of ball rows 58, the shift collar assembly 50 includes at least two circumferential ball columns 59.
The following descriptions of the shift collar positions will be made referencing only one row 58 of drive members or balls 64. It will be understood by those skilled in the art that the same drive paths will apply to any number of additional rows 58 because the balls 64 will be aligned circumferentially in columns 59.
Drive Position
Park Position
Referring to
In the preferred embodiment having twenty-four balls 64, two of the balls of each row 58 (sixteen of the balls 64) are utilized to lock the pinion 24 to the housing 12. In the Park position, the input shaft 20 is rotationally fixed to the shift collar by the middle ball of the row 58, but fixing of the input shaft is not necessary for the Park function. However, because the middle ball is axially aligned with the other balls in the row 58 by the cage apertures 62, the middle ball will align the input shaft groove 22 with grooves 41 and 45 to allow easier shifting out of the Park position than the prior art designs. This is an important feature when the vehicle is in the Park position and is on an incline. In order to shift out of the Park position, alignment of the grooves is necessary and is difficult to achieve when the vehicle is not moving.
Tow Position
Referring to
The yoke 70 is driven by a small electric motor 80. In a preferred embodiment in an electric vehicle, the motor 80 is powered by the vehicle battery pack B. Of course, a manually operated shift lever 90 may also be provided. The motor 80 or shift lever 90 are configured to rotate a pivot arm 76 which in turn rotates a detent plate 78. The detent plate 78 drives a drive pin 79 which is rigidly connected to the yoke 70. A detent assembly 82 engages detents in the detent plate 78 corresponding to the various clutch collar positions, as is well known in the art. A torsion spring 84 engages the drive pin 79 to bias the yoke 70 in a leftward direction as viewed in
The descriptions of specific embodiments of the invention herein are intended to be illustrative and not restrictive. The invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope as defined by the appended claims.
Patent | Priority | Assignee | Title |
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7311016, | Oct 25 2005 | SCHAFER DRIVELINE LLC | Park lock system |
7406888, | Oct 25 2005 | SCHAFER DRIVELINE LLC | Transmission and clutch system |
8261899, | Jul 02 2009 | SCHAFER DRIVELINE LLC | Shifting collar apparatus and method for reducing the force required for disengaging a fixed holding feature |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Apr 10 2015 | SCHAFER DRIVELINE, LLC | (assignment on the face of the patent) | / | |||
Apr 20 2015 | LABENNE, CHRISTOPHER | SCHAFER DRIVELINE, LLC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 035584 | /0467 |
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